Detomidine which is 4-[(2,3-dimethylbenzyl)]imidazole of formula I
is a well known pharmaceutical agent currently used as its hydrochloride salt in animal sedation.
The synthesis of detomidine is described in U.S. Pat. Nos. 4,443,466 and 4,584,383. The preparation of detomidine hydrochloride salt is described in U.S. Pat. No. 4,584,383, wherein detomidine obtained from the hydrogenation step is first recovered from alkaline solution as a free base after which the crystalline product is converted into its hydrochloride salt by treatment with HCl-isopropanol in ethyl acetate.